Method for manufacturing aluminum oxide film for use in semiconductor device

ABSTRACT

A method for manufacturing an aluminum oxide film for use in a semiconductor device, the method including the steps of preparing a semiconductor substrate and setting the semiconductor substrate in a reaction chamber, supplying an aluminum source material and NH 3  gas into the reaction chamber simultaneously for being absorbed on the semiconductor substrate, discharging unreacted MTMA or by-product by flowing nitrogen gas into the reaction chamber or vacuum purging, supplying an oxygen source material into the reaction chamber for being absorbed on the semiconductor substrate, and discharging unreacted oxygen source or by-product by flowing nitrogen gas into the reaction chamber or vacuum purging.

FIELD OF THE INVENTION

[0001] The present invention relates to a method for manufacturing asemiconductor device; and, more particularly, to the method formanufacturing an aluminum oxide for use in the semiconductor device byemploying NH₃ reactive gas to deposit an aluminum source and/or anoxygen source on a wafer.

DESCRIPTION OF THE PRIOR ART

[0002] As is well known, a semiconductor device has a higher degree ofintegration mainly by downsizing through micronization nowadays.However, there is still a demand for downsizing the area of the memorycell, under increased transistor and circuit speeds and improvedreliability. Such demands for increased density, performance andreliability require formation of device features with high precision andminiaturization. To meet the demand, it is necessary to increase acapacitance of a capacitor and improve a gate dielectric film which isapplied for a DRAM and a logic devices. In attempt to solve an aboverequirement, various researches have been advanced to employ the highdielectric materials for a capacitor thin film and a gate dielectricfilm.

[0003] In particular, among the high dielectric materials, aluminumoxide (Al₂O₃) is typically used for the capacitor thin film and the gatedielectric thin film because the aluminum oxide has good oxidationresistance property and thermal stability. Furthermore, it can bepopularly used as a hydrogen barrier for preventing hydrogen diffusion.

[0004] Generally, the aluminum oxide film is formed by using a methodsuch as an atomic layer deposition (ALD). In more detail, amanufacturing steps are as follows: setting a wafer in a chamber;heating up the wafer to 200° C. to 450° C.; supplying an aluminum sourcematerial into the chamber for 0.1 to 3 seconds; flowing N₂ gas into thechamber or vacuum purging for sweeping off unreacted aluminum sourcematerial and by-product; supplying an oxygen source material into thechamber for 0.1 to 3 seconds; and flowing N₂ gas into the chamber orvacuum purging for sweeping off unreacted oxygen source material andby-product, again. This is one cycle for depositing the aluminum oxidefilm. Thus, by repeating this cycle more and more, intended thickness ofaluminum oxide film is obtained.

[0005] In conventional method for manufacturing aluminum oxide film inthe semiconductor device, trimethyl aluminum (TMA, Al(CH₃)₃) or modifiedtrimethyl aluminum (MTMA, Al(CH₃)₃N(CH₂)₅CH₃) is used as the aluminumsource material and vaporized water is usually used as the oxygen sourcematerial.

[0006] However, the conventional method has a drawback that a growthrate of the aluminum oxide is very slow so that productivity maydecrease. And further, the aluminum oxide film formed by theconventional method may contain carbon particles therein due to use ofan organic material such as TMA or MTMA, thereby an electrical propertythereof being deteriorated.

SUMMARY OF THE INVENTION

[0007] It is, therefore, an object of the present invention to provide amethod for manufacturing an aluminum oxide film for use in asemiconductor device by applying NH₃ reactive gas for improving a growthrate of the aluminum oxide film.

[0008] It is another object of the present invention to provide a methodfor manufacturing a semiconductor device incorporating therein analuminum oxide film by applying NH₃ reactive gas for improving a growthrate of the aluminum oxide film.

[0009] In accordance with one aspect of the present invention, there isprovided a method for manufacturing an aluminum oxide film for use in asemiconductor device, the method comprising the steps of: a) preparing asemiconductor substrate and setting the semiconductor substrate in areaction chamber; b) supplying an aluminum source material and NH₃ gasinto the reaction chamber simultaneously for being absorbed on thesemiconductor substrate; c) discharging unreacted MTMA or by-product byflowing nitrogen gas into the reaction chamber or vacuum purging; d)supplying an oxygen source material into the reaction chamber for beingabsorbed on the semiconductor substrate; and e) discharging unreactedoxygen source or by-product by flowing nitrogen gas into the reactionchamber or vacuum purging.

[0010] In accordance with another aspect of the present invention, thereis provided a method for manufacturing an aluminum oxide film for use ina semiconductor device, the method comprising the steps of: a) preparinga semiconductor substrate and setting the semiconductor substrate in areaction chamber; b) supplying an aluminum source material into thereaction chamber for being absorbed on the semiconductor substrate; c)discharging unreacted MTMA or by-product by flowing nitrogen gas intothe reaction chamber or vacuum purging; d) supplying an oxygen sourcematerial and NH₃ gas into the reaction chamber for being absorbed on thesemiconductor substrate; and e) discharging unreacted oxygen source orby-product by flowing nitrogen gas into the reaction chamber or vacuumpurging.

[0011] In accordance with still another aspect of the present invention,there is provided a method for manufacturing an aluminum oxide film foruse in a semiconductor device, the method comprising the steps of: a)preparing a semiconductor substrate and setting the semiconductorsubstrate in a reaction chamber; b) supplying an aluminum sourcematerial and NH₃ gas into the reaction chamber simultaneously for beingabsorbed on the semiconductor substrate; c) discharging unreacted MTMAor by-product by flowing nitrogen gas into the reaction chamber orvacuum purging; d) supplying an oxygen source material and NH₃ gas intothe reaction chamber for being absorbed on the semiconductor substrate;and e) discharging unreacted oxygen source or by-product by flowingnitrogen gas into the reaction chamber or vacuum purging.

[0012] In accordance with further still another aspect of the presentinvention, there is provided a method for manufacturing a semiconductordevice, the method comprising the steps of: a) preparing an activematrix provided with a substrate, isolation regions, gate line, gateoxide and a first insulating layer; b) forming a buffer layer and afirst conductive layer on the active matrix subsequently; c) forming adielectric layer of aluminum oxide (Al₂O₃) on the first conductive layerusing an ALD technique, by supplying NH₃ reactive gas with an aluminumsource and/or an oxygen source; d) forming a second conductive layer onthe dielectric layer and patterning the second conductive layer, thedielectric layer, the first conductive layer and the buffer layer,thereby obtaining a capacitor structure; e) forming a hydrogen barrierlayer on the capacitor structure; f) forming a bit line and a localinterconnection after depositing a second insulating layer; g) forming apassivation layer on entire surface.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects and features of the present inventionwill become apparent from the following description of the preferredembodiments given in conjunction with the accompanying drawings, inwhich:

[0014]FIGS. 1, 2, and 3 are graphs of an exposure time versus athickness of a wafer after depositing an aluminum oxide film by anatomic layer deposition (ALD) technique in accordance with preferredembodiments of the present invention; and

[0015]FIGS. 4A, 4B, 4C and 4E are cross sectional views setting forth amethod for manufacturing a semiconductor device incorporating therein analuminum oxide film in accordance with preferred embodiments of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Referring to FIG. 1, there is a graph of an exposure time versusa thickness of a wafer after depositing an aluminum oxide film during 50cycles by an atomic layer deposition (ALD) technique in accordance witha first preferred embodiment of the present invention.

[0017] In the first embodiment, an aluminum source material and NH₃ gasare supplied into a reaction chamber simultaneously for enhancing agrowth rate of the aluminum oxide film. In comparison with a prior artin which NH₃ gas is not employed, the growth rate of the aluminum oxidefilm in accordance with the present invention is remarkably higher thanthat of the prior art. And further, as the exposure time increases onand on, the growth rate increases also.

[0018] The process for manufacturing the aluminum oxide film isillustrated in more detail hereunder. To begin with, the aluminum sourcematerial and NH₃ gas are supplied into the reaction chambersimultaneously after setting the wafer in the reaction chamber, forbeing absorbed on a surface of the wafer. And then, a first purge iscarried out for sweeping off unreacted aluminum oxide and by-productafter stopping supplying the aluminum source. In a next step, oxygensource material is supplied into the reaction chamber for being absorbedon the surface of the wafer. Thereafter, a second purge is carried outfor sweeping off unreacted oxygen source material and by-product. Thisis one cycle for depositing the aluminum oxide film. Repeating the cyclemany times, the aluminum oxide film with an intended thickness is formedon the wafer. After depositing the aluminum oxide completely, anannealing process is performed for densifying the aluminum oxide film.

[0019] Here, a deposition temperature is kept up to 200° C. to 450° C.and the pressure in the chamber is kept at 50 mTorr to 300 mTorr. Thealuminum source material, e.g., trimethyl aluminum (TMA, Al(CH₃)₃) ormodified trimethyl aluminum (MTMA, Al(CH₃)₃N(CH₂)₅CH₃), is suppliedthrough a first supply-pipe for 0.1 to 3 seconds. Meanwhile, NH₃ gas issupplied into the reaction chamber simultaneously through a secondsupply-pipe, a flow rate being 20 to 1,000 standard cubic centimetersper minute (sccm). If NH₃ gas and the aluminum source material aresupplied into the chamber through the same supply-pipe, the aluminumsource reacts with NH₃ gas, thereby producing particles in thesupply-pipe. Thus, the aluminum source material and NH₃ gas should besupplied through each separate supply-pipe. The first purge is carriedout for 0.1 to 3 seconds to discharge unreacted aluminum source materialand by-product through a discharge pump, but it may be carried out byusing a method such as a vacuum purging. In addition, the oxygen sourcematerial, e.g., vaporized water, is supplied for 0.1 to 3 secondsthrough a third supply-pipe, and then, the second purge is carried outas similar to the first purge.

[0020] Since the aluminum oxide film employs metal-organic material suchas TMA or MTMA, the aluminum oxide film contains carbon particlestherein after deposition reaction, thereby deteriorating electricalproperty at last. To avoid the deterioration of electrical property, afollowing process is carried out at 300° C. to 450° C., by using amethod such as O₂ plasma, N₂O plasma, Ex-PNT, UV/O₃ or the like. Andfurther, an annealing process is performed at 650° C. to 850° C. fordensifying the aluminum oxide film.

[0021] Referring to FIG. 2, there is another graph of an exposure timeversus a thickness of a wafer after depositing an aluminum oxide filmduring 50 cycles by an atomic layer deposition (ALD) technique inaccordance with a second preferred embodiment of the present invention.

[0022] In the second embodiment, an oxygen source material and NH₃ gasare supplied into a reaction chamber simultaneously for enhancing agrowth rate of the aluminum oxide film. In comparison with a prior artin which NH₃ gas is not employed, the growth rate of the aluminum oxidefilm in accordance with the present invention is remarkably higher thanthat of the prior art. And further, as the exposure time increases onand on, the growth rate increases also.

[0023] The process for manufacturing the aluminum oxide film inaccordance with the second embodiment is illustrated in more detailhereunder. To begin with, the aluminum source material is supplied intothe reaction chamber after setting the wafer in the reaction chamber,for being absorbed on a surface of the wafer. And then, a first purge iscarried out for sweeping off unreacted aluminum oxide and by-productafter stopping supplying the aluminum source. In a next step, oxygensource material and NH₃ re supplied into the reaction chambersimultaneously for being absorbed on the surface of the wafer.Thereafter, a second purge is carried out for sweeping off unreactedoxygen source material and by-product. This is one cycle for depositingthe aluminum oxide film. Repeating the cycle many times, the aluminumoxide film with an intended thickness is formed on the wafer. Afterdepositing the aluminum oxide, a process for removing carbon particlesan annealing process are performed sequentially.

[0024] Here, a deposition temperature is kept up to 200° C. to 450° C.and the pressure in the chamber is kept at 50 mTorr to 300 mTorr. Thealuminum source material, e.g., trimethyl aluminum (TMA, Al(CH₃)₃) ormodified trimethyl aluminum (MTMA, Al(CH₃)₃N(CH₂)₅CH₃), is suppliedthrough a first supply-pipe for 0.1 to 3 seconds. The first purge iscarried out for 0.1 to 3 seconds to discharge unreacted aluminum sourcematerial and by-product through a discharge pump, but it may be carriedout by using a method such as a vacuum purging. In addition, the oxygensource material, e.g., vaporized water, and NH₃ gas are supplied for 0.1to 3 seconds through the second supply-pipe, a flow rate being 20 to1,000 sccm. And the second purge is carried out as similar to the firstpurge. Here, if the oxygen source material and NH₃ gas are suppliedthrough each supply-pipe, there may be produced lot of particles in thechamber due to reaction of water and NH₃ gas. Thus, they should besupplied through the same supply-pipe.

[0025] Since the aluminum oxide film employs metal-organic material suchas TMA or MTMA, the aluminum oxide film contains carbon particlestherein after deposition reaction, thereby deteriorating electricalproperty at last. To avoid the deterioration of electrical property, afollowing process is carried out at 300° C. to 450° C., by using amethod such as O₂ plasma, N₂O plasma, Ex-PNT, UV/O₃ or the like. Andfurther, an annealing process is performed at 650° C. to 850° C. fordensifying the aluminum oxide film.

[0026] Referring to FIG. 3, there is still another graph of an exposuretime versus a thickness of a wafer after depositing an aluminum oxidefilm for during cycles by an atomic layer deposition (ALD) technique inaccordance with a third preferred embodiment of the present invention.

[0027] In the third embodiment, an aluminum source material and NH₃ gasare supplied into a reaction chamber simultaneously and further, anoxygen source material and NH₃ gas are also supplied simultaneously, forenhancing a growth rate of the aluminum oxide film. In comparison with aprior art in which NH₃ gas is not employed, the growth rate of thealuminum oxide film in accordance with the present invention isremarkably higher than that of the prior art. And further, as theexposure time increases on and on, the growth rate increases also.

[0028] The process for manufacturing the aluminum oxide film inaccordance with the third embodiment is illustrated in more detailhereunder. To begin with, the aluminum source material and NH₃ gas aresupplied into the reaction chamber simultaneously after setting thewafer in the reaction chamber, for being absorbed on a surface of thewafer. And then, a first purge is carried out for sweeping off unreactedaluminum oxide and by-product after stopping supplying the aluminumsource. In a next step, oxygen source material and NH₃ gas are suppliedinto the reaction chamber simultaneously for being absorbed on thesurface of the wafer. Thereafter, a second purge is carried out forsweeping off unreacted oxygen source material and by-product. This isone cycle for depositing the aluminum oxide film. Repeating the cyclemany times, the aluminum oxide film with an intended thickness is formedon the wafer. After depositing the aluminum oxide, a process forremoving carbon particles an annealing process are performedsequentially.

[0029] Here, a deposition temperature is kept up to 200° C. to 450° C.and the pressure in the chamber is kept at 50 mTorr to 300 mTorr. Thealuminum source material, e.g., trimethyl aluminum (TMA, Al(CH₃)₃) ormodified trimethyl aluminum (MTMA, Al(CH₃)₃N(CH₂)₅CH₃), is suppliedthrough a first supply-pipe for 0.1 to 3 seconds. Meanwhile, NH₃ gas issupplied into the reaction chamber simultaneously through a secondsupply-pipe, a flow rate being 20 to 1,000 sccm. If NH₃ gas and thealuminum source material are supplied into the chamber through the samesupply-pipe, the aluminum source reacts with NH₃ gas, thereby producingparticles in the pipe. Thus, the aluminum source material and NH₃ gasshould be supplied through each separate supply-pipe. The first purge iscarried out for 0.1 to 3 seconds to discharge unreacted aluminum sourcematerial and by-product through a discharge pump, but it may be carriedout by using a method such as a vacuum purging. In addition, the oxygensource material and NH₃ gas are supplied for 0.1 to 3 seconds throughthe third supply-pipe, a flow rate being 20 to 1,000 sccm. And thesecond purge is carried out as similar to the first purge. Here, if theoxygen source material and NH₃ gas are supplied through each separatesupply-pipe, there may be produced lot of particles in the chamber dueto reaction of water and NH₃ gas.

[0030] Since the aluminum oxide film employs metal-organic material suchas TMA or MTMA, the aluminum oxide film contains carbon particlestherein after deposition reaction, thereby deteriorating electricalproperty at last. To avoid the deterioration of electrical property, afollowing process is carried out at 300° C. to 450° C., by using amethod such as O₂ plasma, N₂O plasma, Ex-PNT, UV/O₃ or the like. Andfurther, an annealing process is performed at 650° C. to 850° C. fordensifying the aluminum oxide film.

[0031] Referring to FIGS. 4A to 4E, there are provided cross sectionalviews setting forth a method for manufacturing a semiconductor deviceincorporating therein an aluminum oxide film in accordance with a fourthpreferred embodiment by applying the aluminum oxide deposition method ofthe present invention.

[0032] The process for manufacturing the semiconductor device beginswith a preparation of an active matrix 110 including a semiconductorsubstrate 102, an isolation region 104, diffusion regions 106, a gateoxide 112, a gate line 113, a spacer 114 and a first insulating layer116. One of the diffusion regions 106 serves as a source and the otherdiffusion region 106 serves as a drain.

[0033] Thereafter, a buffer layer 118, a first conductive layer 120, adielectric layer 122 and a second conductive layer 124 are formed on topof the active matrix 118 subsequently, as shown in FIG. 4A. In thefourth preferred embodiment, the dielectric layer 122 is made ofaluminum oxide (Al₂O₃) by using a method such as an atomic layerdeposition (ALD) technique, wherein the deposition pressure isapproximately 50 to 300 mTorr and the deposition temperature is kept at200° C. to 450° C. Here, the buffer layer 118 is formed to improveadhesion between the first insulating layer 116 and the first conductivelayer 120.

[0034] Since the method for depositing the aluminum oxide of thedielectric layer 122 is illustrated in the first, the second and thethird embodiment, the detailed description will be abbreviated here.

[0035] In a subsequent step, the second conductive layer 124, thedielectric layer 122, the first metal layer 120 and the buffer layer 118are patterned into a predetermined configuration, thereby obtaining acapacitor structure 150 having a buffer 118A, a bottom electrode 120A, acapacitor thin film 122A and a top electrode 124A, as shown in FIG. 4B.It is preferable that the bottom electrode 120A has a size differentfrom that of the top electrode 128A in order to form a plate line (notshown) during the following processes.

[0036] In a next step as shown in FIG. 1C, a hydrogen barrier layer ofan aluminum oxide is formed on the capacitor structure 150 and portionsof the first insulating layer 116, for preventing the capacitorstructure 150 from hydrogen penetration thereinto during a postmanufacturing process, e.g., a passivation process. Since, the methodfor forming the aluminum oxide layer by the ALD technique is same tothose of the capacitor thin film 122A, the detailed description isabbreviated here.

[0037] Thereafter, according to the exemplary process for fabricatingthe semiconductor device, a second insulating layer 130 is formed on thecapacitor structure 150 and the first insulating layer 116. And then,they are patterned into a third predetermined configuration, therebyobtaining openings 132, 134, 136 as shown in FIG. 1D. In a subsequentstep, a third conductive layer is formed on the entire surface includingthe interiors of the openings 132, 134, 136 and patterned so that a bitline 144B and a local interconnection 144A are obtained. And finally, apassivation layer 152 is formed on entire surface by using a CVD or PVDmethod as shown in FIG. 1E.

[0038] In the fourth embodiment of the present invention, the gate oxidefilm 112 can also be made of the aluminum oxide film by using thealuminum oxide deposition method of the present invention.

[0039] In comparison with the prior art, the present invention providesthe aluminum oxide deposition method with the enhanced growth rate bysupplying NH₃ reactive gas with the aluminum source material and/or theoxygen source material simultaneously. Moreover, by annealing thealuminum oxide film after depositing it completely on the wafer, it ispossible to obtain the dense aluminum oxide film.

[0040] Although the preferred embodiments of the invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. A method for manufacturing an aluminum oxide filmfor use in a semiconductor device, the method comprising the steps of:a) preparing a semiconductor substrate and setting the semiconductorsubstrate in a reaction chamber; b) supplying an aluminum sourcematerial and NH₃ gas into the reaction chamber simultaneously for beingabsorbed on the semiconductor substrate; c) discharging an unreactedMTMA or by-product by flowing a nitrogen gas into the reaction chamberor vacuum purging; d) supplying an oxygen source material into thereaction chamber for being absorbed on the semiconductor substrate; ande) discharging an unreacted oxygen source or by-product by flowing anitrogen gas into the reaction chamber or vacuum purging.
 2. The methodof claim 1 , b) to e) steps are carried out repeatedly by using anatomic layer deposition (ALD) technique until an aluminum oxide with apredetermined thickness is formed on the semiconductor substrate.
 3. Themethod of claim 1 , wherein a deposition temperature is kept at 200° C.to 450° C. and a deposition pressure is at 50 mTorr to 300 mTorr.
 4. Themethod of claim 1 , wherein the aluminum source material includes ametal-organic material of trimethyl aluminum (TMA) or modified trimethylaluminum (MTMA)
 5. The method of claim 1 , wherein the aluminum sourcematerial and NH₃ gas are supplied, each through a separate supply-pipeinto the reaction chamber for 0.1 to 3 seconds.
 6. The method of claim 5, wherein the NH₃ gas is supplied at a flow rate of 20 sccm to 1,000sccm.
 7. The method of claim 1 , wherein the oxygen source materialincludes vaporized water
 8. The method of claim 7 , wherein the oxygensource material is supplied to the reaction chamber for 0.1 to 3seconds.
 9. The method of claim 7 , after e) step, further comprisingthe steps of: f) removing carbon particles in the aluminum oxide film;and g) annealing the aluminum oxide film for densification thereof at650° C. to 850° C. in a N₂ rich atmosphere.
 10. The method of claim 9 ,wherein f) step is carried out at 300° C. to 450° C. by using a materialselected from a group of O₂ plasma, N₂O plasma, Ex-PNT and UV/O₃.
 11. Amethod for manufacturing an aluminum oxide film for use in asemiconductor device, the method comprising the steps of: a) preparing asemiconductor substrate and setting the semiconductor substrate in areaction chamber; b) supplying an aluminum source material into thereaction chamber for being absorbed on the semiconductor substrate; c)discharging an unreacted MTMA or by-product by flowing a nitrogen gasinto the reaction chamber or vacuum purging; d) supplying an oxygensource material and a NH₃ gas into the reaction chamber for beingabsorbed on the semiconductor substrate; and e) discharging unreactedoxygen source or by-product by flowing a nitrogen gas into the reactionchamber or vacuum purging.
 12. The method of claim 11 , b) to e) stepsare carried out repeatedly by using an atomic layer deposition (ALD)technique until the aluminum oxide with a predetermined thickness isformed on the semiconductor substrate.
 13. The method of claim 11 ,wherein a deposition temperature is kept at 200° C. to 450° C. and adeposition pressure is at 50 mTorr to 300 mTorr.
 14. The method of claim11 , wherein the aluminum source material includes a metal-organicmaterial of trimethyl aluminum (TMA) or modified trimethyl aluminum(MTMA)
 15. The method of claim 11 , wherein the oxygen source materialand NH₃ gas are supplied into the reaction chamber for 0.1 to 3 secondsthrough a same supply-pipe.
 16. The method of claim 15 , wherein the NH₃gas is supplied at a flow rate of 20 sccm to 1,000 sccm.
 17. The methodof claim 11 , wherein the oxygen source material is vaporized water. 18.The method of claim 17 , wherein the oxygen source material is suppliedto the reaction chamber for 0.1 to 3 seconds.
 19. The method of claim 17, after e) step, further comprising the steps of: f) removing carbonparticles in the aluminum oxide film; and g) annealing the aluminumoxide film for densification thereof at 650° C. to 850° C. in a N₂ richatmosphere.
 20. The method of claim 19 , wherein f) step is carried outat 300° C. to 450° C. by using a material selected from a group of O₂plasma, N₂O plasma, Ex-PNT and UV/O₃.
 21. A method for manufacturing analuminum oxide film for use in a semiconductor device, the methodcomprising the steps of: a) preparing a semiconductor substrate andsetting the semiconductor substrate in a reaction chamber; b) supplyingan aluminum source material and a NH₃ gas into the reaction chambersimultaneously for being absorbed on the semiconductor substrate; c)discharging an unreacted MTMA or by-product by flowing a nitrogen gasinto the reaction chamber or vacuum purging; d) supplying an oxygensource material and a NH₃ gas into the reaction chamber for beingabsorbed on the semiconductor substrate; and e) discharging an unreactedoxygen source or by-product by flowing a nitrogen gas into the reactionchamber or vacuum purging.
 22. The method of claim 21 , b) to e) stepsare carried out repeatedly by using an atomic layer deposition (ALD)technique until an aluminum oxide with a predetermined thickness isformed on the semiconductor substrate.
 23. The method of claim 21 ,wherein a deposition temperature is kept at 200° C. to 450° C. and adeposition pressure is at 50 mTorr to 300 mTorr.
 24. The method of claim21 , wherein the aluminum source material includes a metal-organicmaterial of trimethyl aluminum (TMA) or modified trimethyl aluminum(MTMA)
 25. The method of claim 21 , wherein the aluminum source materialand NH₃ gas are supplied, each through a separate supply-pipe, into thereaction chamber for 0.1 to 3 seconds and the aluminum source materialand NH₃ gas are supplied into the reaction chamber for 0.1 to 3 secondsthrough a same supply-pipe.
 26. The method of claim 25 , wherein NH₃ gasis supplied at a flow rate of 20 sccm to 1,000 sccm.
 27. The method ofclaim 21 , wherein the oxygen source material is vaporized water
 28. Themethod of claim 27 , wherein the oxygen source material is supplied tothe reaction chamber for 0.1 to 3 seconds.
 29. The method of claim 27 ,after e) step, further comprising the steps of: f) removing carbonparticles in the aluminum oxide film; and g) annealing the aluminumoxide film for densification thereof at 650° C. to 850° C. in N₂ richatmosphere.
 30. The method of claim 29 , wherein f) step is carried outat 300° C. to 450° C. by using a material selected from a group of O₂plasma, N₂O plasma, Ex-PNT and UV/O₃.
 31. A method for manufacturing asemiconductor device, the method comprising the steps of: a) preparingan active matrix provided with a substrate, isolation regions, a gateline, a gate oxide and a first insulating layer; b) forming sequentiallybuffer layer and a first conductive layer on the active matrix; c)forming a dielectric layer having an aluminum oxide (Al₂O₃) on the firstconductive layer using an atomic layer deposition (ALD) technique, bysupplying a NH₃ reactive gas with an aluminum source and/or an oxygensource; d) forming a second conductive layer on the dielectric layer andpatterning the second conductive layer, the dielectric layer, the firstconductive layer and the buffer layer, thereby obtaining a capacitorstructure; e) forming a hydrogen barrier layer on the capacitorstructure; f) forming a bit line and a local interconnection afterdepositing a second insulating layer; g) forming a passivation layer onentire surface of the substrate.
 32. The method of claim 31 , whereinthe gate oxide includes aluminum oxide formed by using an atomic layerdeposition (ALD) technique, by supplying the NH₃ reactive gas with thealuminum source and/or oxygen source.
 33. The method of claim 32 ,wherein the hydrogen barrier layer includes an aluminum oxide formed byusing an atomic layer deposition (ALD) technique, by supplying NH₃reactive gas with an aluminum source and/or an oxygen source.
 34. Themethod of claim 31 , after c) step, further comprising the step ofannealing the dielectric layer for densification thereof.
 35. The methodof claim 34 , wherein the step of annealing the dielectric layer iscarried out at 650° C. to 850 ° C. in a N₂ rich ambient.